Mysteries of Irish glacio-karst

The Burren is an iconic (surely the best ever?) example of glacio-karst. While its expansive limestone pavements support a sparse, patchy soil cover today, a growing body of evidence suggests this cover was greater in the geologically recent past, prompting the questions: How did soils originate on a glaciated limestone substrate? Where have these soils gone subsequently? Our initial focus working here was the first question. Caving fanatic and Burren aficionado, Colin Bunce, holds court at the centre of all my Burren science, having approached me in 2019 about jointly exploring its weird soils and confounding geomorphology. 

Our initial focus was - and remains - the thin mineral soils throughout the Burren: our investigations suggest strongly that these are loess deposits, a fine-grained wind-transported quartz silt that has its origins in the end of the last ice age. We named this GSI-funded project 'Ireland's Dust Bowl' and it continues to produce great finds (we're currently writing the first paper). Our subsequent project ('What lies beneath') takes us beneath the surface, into the Burren's underland. Again, GSI is providing the funding for our team to apply a suite of geological and geochemical tools to figure out the genesis and meaning of thick rhythmite deposits found in many Burren caves. Do these represent subglacial drainage during the ice ages? Or postglacial inundation of the karstscape by silt-laden meltwater lakes during the termination? Or something else entirely? 

Collaborators: Colin Bunce, Martin Nauton, Shane Tyrrell, Dave O'Leary, Tiernan Henry, & Audrey Morley (Galway), Nick Scroxton (Maynooth), Frank McDermott (University College Dublin), Eamon Doyle (Burren & Cliffs of Moher Geopark), David Chew (Trinity), Thomas Stevens (Uppsala), Kathryn Fitzsimmons (Monash), Tobias Lauer (Tubingen) 

Students/Postdocs/RAs: Marta Carbello (Galway)

Funded by Geological Survey Ireland.

Related Publications 

Herbert, J.N., Bromley, G.R., et al., 2025. Paleoclimatic implications of glacial fluctuations in the Sierra Nevada del Cocuy, northern Andes, Colombia, during the Lateglacial and Holocene. Quaternary Science Reviews 363, p.109458

Gorin, A.L., Shakun, J.D., Jones, A.G., Kennedy, T.M., Marcott, S.A., Goehring, B.M., Zoet, L.K., Jomelli, V., Bromley, G.R., et al., 2024. Recent tropical Andean glacier retreat is unprecedented in the Holocene. Science 385, 517-521.

Bromley, G.R.M., et al., 2016. A cosmogenic 10Be chronology for the local last glacial maximum and termination in the Cordillera Oriental, southern Peruvian Andes: Implications for the tropical role in global climate. Quat. Sci. Rev. 148, 54–67.  

Bromley, G.R.M., et al., 2011. Late Pleistocene snowline fluctuations at Nevado Coropuna (15S), southern Peruvian Andes. J. Quat. Sci. 26, 305-317.

Bromley, G.R.M., et al., 2011. Glacier fluctuations in the southern Peruvian Andes during the late-glacial period, constrained with cosmogenic 3He. J. Quat. Sci. 26, 37-46.

Bromley, G.R.M., et al., 2009. Relative timing of last glacial maximum and late glacial events in the tropical Andes. Quaternary Science Reviews 28, 2514-2526.

Glacial geologist maps clues to global climate change from the Andes Mountains (Medill School of Journalism)

Climate in the Peruvian Andes: From Early Humans to Modern Challenges (Columbia Climate School)